SUPERMASSIVE BLACK HOLES AND THEIR HOST SPHEROIDS. II. THE RED AND BLUE SEQUENCE IN THE M_BH–M_*,SPH DIAGRAM

Abstract

In our first paper, we performed a detailed (i.e., bulge, disks, bars, spiral arms, rings, halo, nucleus, etc.) decomposition of 66 galaxies, with directly measured black hole masses, M BH , imaged at 3.6 m m with Spitzer. Our sample is the largest to date and, for the first time, the decompositions were checked for consistency with the galaxy kinematics. We present correlations between M BH and the host spheroid (and galaxy) luminosity, L sph (and L gal ), and also stellar mass, M .,sph * While most previous studies have used galaxy samples that were overwhelmingly dominated by high-mass, early-type galaxies, our sample includes 17 spiral galaxies, half of which have M M 10 , argued by some to be pseudo-bulges, are not offset to lower M BH from the correlation defined by the current bulge sample with n 2; sph > and (3)L sph and L gal correlate equally well with M BH , in terms of intrinsic scatter, only for early-type galaxies-once reasonable numbers of spiral galaxies are included, the correlation with L sph is better than that with L gal .

Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation

“…We will consider five different black hole samples 1 : those of Savorgnan et al (2016), Läsker et al (2014), McConnell & Ma (2013), Beifiori et al (2012), and Saglia et al (2016). The other five samples are based on the same sample of local galaxies with dynamical mass measurements of the central black hole, but with different estimates of the host galaxy velocity dispersion and luminosity.…”

“…Indeed, nuclear kinematics of a number of nearby galaxies show the clear signature of a central mass concentration, beyond what can be attributed to the observed stellar population ⋆ E-mail: F.Shankar@soton.ac.uk in the nuclear regions. Black hole masses, M bh , are found to correlate with several global properties of their host galaxies (see, e.g., Ferrarese & Ford 2005;Shankar 2009; Kormendy & Ho 2013;Graham 2016, for reviews), including the stellar and/or bulge mass, velocity dispersion, σ, luminosity, light concentration or Sérsic index (e.g., Magorrian et al 1998;Richstone et al 1998 Kormendy & Ho 2013;McConnell & Ma 2013;Scott et al 2013;Läsker et al 2014;Savorgnan & Graham 2015a;Savorgnan et al 2016;Saglia et al 2016), and the mass of the surrounding dark matter halo (e.g., Ferrarese 2002a; Baes et al 2003;Bogdán & Goulding 2015;Sabra et al 2015). However, while it is true that the number of dynamical black hole mass measurements has increased over the years, such samples still remain relatively small, of the order of ∼ 70 − 80 galaxies.…”

Selection bias in dynamically measured supermassive black hole samples: scaling relations and correlations between residuals in semi-analytic galaxy formation models

“…log Y | log X . The magenta long-dashed and dotted lines in each panel show the best fit and 1σ uncertainties on the correlations between residuals in the Savorgnan et al (2016) dataset: red circles and green triangles represent ellipticals and lenticulars. We obtained the magenta lines by running 200 iterations following the steps outlined in Shankar et al (2017), which include errors in both variables.…”

“…Long-dashed red lines are the intrinsic scaling relations as inferred from Monte Carlo simulations by Shankar et al (2016). Blue diamonds are data collected and updated by Savorgnan et al (2016) on local galaxies with dynamical measurements of supermassive black holes. Note that observational biases can increase the normalisation and reduce the scatter in the intrinsic scaling relations.…”

“…We restrict to this specific SDSS subsample as velocity dispersions in late-type galaxies are not spatially resolved, though the correlation does not depend on the exact cut in p(E+S0). For consistency with the data of Savorgnan et al (2016) to which we will compare, we follow Shankar et al (2016) and correct the velocity dispersions σHL, as in Cappellari et al (2006), to a common aperture of 0.595 kpc (i.e. the one adopted by the Hyperleda data base, Paturel et al 2003).…”